Arc-lamp electrode.



No. 883,924. PATENTED APR. 7, 1908.

W. S. WEEDON.

ARC LAMP ELECTRODE.

APPLICATION FILED Am. 21, 1903.

Fig. 1

Witnesses: Inventor:

./ QJT I William S.Weed on I UNITED STATES PATENT OFFICE WILLIAM S. WEEDON, OF SCIIENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ARC-LAMP ELECTRODE.

Specification of Letters Patent.

Patented April 7, 1908.

Application filed April 21, 1901}. Serial N 0. 153,621.

- a citizen of the United States, residingat Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Arc-Lamp Electrodes, of which the following is a specification. I

An electrode composed rincipally or entirely of titanium carbid or use in an arc lamp has been found to possess extraordinary li ht-giving qualities. After such electrodes lave been used, it is found, however, that in that portion of the electrode which is heated to an oxidizing temperature by the arc, a considerable portion of the carbid is converted into titanium oxid without vaporization. The extreme end of the electrode is more or less compact, but back some distance from the end the electrode is not homo-' geneous and compact, but is full of fissures and possesses little mechanical strength. As the oxidation continues, tion of the tip end of the electrode, containing titanium both in the form ofthe oxid and the carbid not yet converted into oxid, loses its cohesiveness so that the tip breaks away and is lost. This is of course objectionable, as it materially increases the consumption of the electrode and interferes with the, proper o eration of the electrode. I have found t at this injurious oxidation of the electrode can be prevented by incasing the titanium carbid in a suitable sheath or casing. The sheath or casing should be made of some material which is not readily affected by the heat produced in operation or other conditions of use, or which under those conditions forms compounds which protect the carbid from the air. The material which I ordinarily employ for the sheath is copper, and I prefer to apply the copper to the titanium' carbid by electro-deposition, as I can thereby obtain a very thin layer of copper intimately connected to the titanium carbid.

For a better understanding of my invention, reference may be had to the accompanying drawings,.Figure 1 of which illustrates a sectional elevation of an electrode made in accordance with my invention, and Fig. 2 illustrates an electrode composed of tit'anium carbid which has been used without a protecting sheath or casing to prevent oxidation.

at O in Fig. 2.

a considerable portrode takes place at intervals; This core or pencil formed wholly or partially of titanium carbid, and B represents a thin, protecting sheath or casing of copper which is preferably electro-plated on the carbid core.

The arc end of thetitanium carbid electrode without a protecting casing is indicated When so used, progressive oxidation of the electrode takes place from the surface of the electrode inward between {he upper end of the electrodes and the line he distance between the arc end of the electrode and this line D, which marks the limit of the portion of the electrodes heatedv to an oxidizlng tem erature by the current, is determined by t e dimenslons and construction of the electrode and the conditions of use. The portion above the line D swells up as oxidation takes place and disintegrates,

fissures being formed as indicated at E I The weakenin of the electrode is most notice able close y adjacent to'the line, D. At the arc surface the material'composing the elec .--trode becomes metallic in appearance and effect does not extend Eventually substantially veryhard, but this back very. far.

all that portion of the electrode above the line D separates from the main portion of the electrode and drops off. 1 In the further use of the electrode a similar oxidation and breakingaway of a considerable portionof the elecduces a serious waste of the electrode and interferes with the steadiness'of the light produced and .is otherwise objectionable.

When the electrode is "incased in copper,

however, as in Fig. 1, none of these results The copper and copper oxi d or pro-' 1. An electrode consisting of titanium car- I v bid incasedin a cop er sheath.

2. An arc electro e. consisting of a core or pencil formed of a material which crumbles when heated inair, and a casing therefor, which onl vaporizes near the arc and thus protects t e heated portion ofthe coreor.

pencil back of the are from access of air.

3. An electrode consisting of a core or penoil containing titanium carbid and electroplated to revent crumbling when heated.

4/ An e ectrode consistin of a core or pencil containing titanium car id and a casi therefor formed of some material which w ill prevent injurious oxidation of the titanium carbid when heated.

5. An electrode consistin of a core or pencil containing titanium car id, and a casin or sheath therefor formed of some materia I the oxids of which are stable at c ompar atively high temperature.

6; An electrode consisting of a core or pen- 011 formed of a carbid and a casing or. sheath 15 therefor of co per.

7. An are e ectrode made of such material that the tip together with a portion back of thearc tends to separate from the body of the electrode when 'ghly heated in air, and

means for preventing such separation com- 1 prising a' copper casing or sheath.

8. An electrode com risin a core formed of a metallic carbid w 'ch 1s stable in the presence of atmospheric moisture, and a. protective coating therefor.

In witness whereof I have hereunto set my hand this 18th day of April 1903.

WILLIAM. s. 'WEEDON.

Witnesses:

EDWARD WILLIAMS, Jr., MARCUS L. BYNG. 

